Method and apparatus for generation and implantation of ions

Abstract

A surface ion source creates a high purity ion beam of molecules of metal compounds having a lower ionization energy than the metal they contain. Low energy dispersion in the ion beam and currents on the order of one ampere are attainable over long duration operation. Rhenium is used in the ion source and related catalyzer. Temperatures vary in the range of 700 to 2500 degrees centigrade and a preferred vacuum pressure of 10 -5 torr, or lower, is used. Wear and corrosion resistance of a wide variety of materials is greatly enhanced through ion deposition and/or implantation with the disclosed apparatus and methods.

I claim: 
     
       1. Apparatus for generating molecular ions, said apparatus including container means for containing a gaseous ion source material comprised of a metal, means for chemically synthesizing the gaseous ion source material in the form of molecules of a metal compound having a lower ionization energy than the metal that it contains, and means for ionizing said molecules. 
     
     
       2. Apparatus as defined in claim 1 wherein said metal compound is selected from the group consisting of compounds of the lanthanides, yttrium, scandium, actinium, zirconium, titanium, and the alkaline earths. 
     
     
       3. Apparatus as defined in claim 1 wherein said metal compound is selected from the group consisting of the monoxides of lanthanum, yttrium, cerium, praseodymium, neodymium, samarium, uranium, gadolinium, terbium, scandium, actinium, zirconium and titanium. 
     
     
       4. Apparatus as defined in claim 1 wherein said means for chemically synthesizing the gaseous ion source material is comprised of a surface catalyzer. 
     
     
       5. Apparatus as defined in claim 4 wherein said surface catalyzer is comprised of rhenium. 
     
     
       6. Apparatus for generating ions, said apparatus comprising container means for containing metal material to be ionized, vaporizing means for vaporizing said metal material, a mixing chamber and a passageway connected thereto for transporting said vaporized metal material from said container and through said mixing chamber, means for introducing reactant means into said mixing chamber and said passageway for creating molecules of a metal compound having a lower ionization energy than said metal, a surface ion source located downstream of said passageway for ionizing said molecules, and means for causing said ionized molecules to emerge from said surface ion source. 
     
     
       7. Apparatus as defined in claim 6 including means for heating said surface ion source to a temperature in excess of 700 degrees C. but less than the melting point thereof. 
     
     
       8. Apparatus as defined in claim 6 wherein said surface ion source is formed of rhenium. 
     
     
       9. Apparatus as defined in claim 6 wherein said passageway is defined by surface catalyzer members formed of rhenium. 
     
     
       10. Apparatus as defined in claim 6 including said mixing chamber comprises a plenum located between said container means and said passageway, and said reactant means for introducing into said plenum a gas selected from the group consisting of oxygen, the halogens and pseudo-halogens. 
     
     
       11. Apparatus as defined in claim 6 wherein said means for causing said ionized molecules to emerge from said surface ion source includes means for extracting a current output from said surface ion source greater than one milliampere of molecular ions. 
     
     
       12. A method for treating a substrate, said method including the steps of providing an ion source material comprised of a metal, combining said metal with a reactant for creating molecules of a metal compound having a lower ionization energy than the metal it contains, creating ions of said metal compound, and causing said ions to impinge on said substrate. 
     
     
       13. A method as defined in claim 12 further including the step of selecting said metal compound from the group consisting of the lanthanides, yttrium, scandium, actinium, zirconium, titanium, uranium and the alkaline earths. 
     
     
       14. A method as defined in claim 12 further including the step of selecting said reactant from the group consisting of oxygen, the halogens and the pseudo-halogens. 
     
     
       15. A method as defined in claim 12 further including the steps of providing a mixing chamber and a passageway connected to said mixing chamber, creating a vacuum in an enclosed pressure chamber containing said mixing chamber and said passageway, said step of combining said metal with said reactant including the step of creating a metal vapor of said ion source material, introducing said metal vapor and said reactant into said passageway for forming said molecules, depositing said molecules upon a surface ion source located adjacent said passageway for producing ions of said molecules, and applying a voltage across said surface ion source for extracting said ions therefrom. 
     
     
       16. A method as defined in claim 15 wherein said voltage is on the order of one kilovolt or higher, and said method includes the addition step of providing a vacuum on the order of 10 -5  torr adjacent said surface ion source on the side thereof remote from said passageway. 
     
     
       17. A method as defined in claim 12 further including the step of producing a current of said ions in excess of one milliampere. 
     
     
       18. The method as defined in claim 12 wherein the step of causing said ions to impinge on said substrate includes the step of causing said ions in excess of 10 15  ions per square centimeter to impinge on said substrate. 
     
     
       19. A method of treating a substrate with ions, said method comprising the steps of providing a substrate to be treated, implanting said substrate with ions comprised of metal by creating ions for forming an ion stream and moving said ion stream into contact with said substrate, the improvement comprising the step of forming molecular ions from molecules which have a lower ionization energy than the metal they contain, and implanting the substrate with said molecular ions. 
     
     
       20. A method as defined in claim 19 further including the step of choosing said molecules from the group consisting of the monovalent and divalent rare earths, the monovalent alkaline earths, the monovalent, divalent and trivalent species of titanium and zirconium, the divalent and tetravalent species of uranium, and the organo-metallics. 
     
     
       21. The method of claim 20 further including the step of introducing gaseous oxygen for forming metal oxide ions.